The face of rock music is changing - its sweaty, jagged features again emerging from the glossy, corporate cosmetics of recent years.

The "superstars" are still selling records. The cardboard cowboys of California are still twanging away. The Southern boogie madmen continue to abuse the blues. And the heavy metal is clanking as loudly as ever. But there are new rockers who are gradually selling records on an expanding scale. They have been nurtured by the punk and new wave movements, yet are managing to transform those stylistic limitations into viable pop products.

The Cars and Gruppo Sportivo are bold representatives of this new movement. Their music is rough and hardedged yet with a sophistication and imagination sorely lacking in rock. They are just starting, but they could become just popular enough to make the Jackson Brownes quake in their boots and the Doobies and their ilk choke on their grits.

While a late-'70s musical monstrosity like Boston is still plodding around the country inflicting its electronic tomfoolery on the public, fellow Bostonians - the Cars - are racing up the charts with their own form of straight-ahead rock. Their first self-titled record is selling strongly after a year, and their new release, "Candy O" (Elektra 5E-507), seems to be blaring from every car radio in the country.

The Cars offer an intriguing compromise of various styles: a unique comination of new wave and pop, with enough melodic hooks and musicality to appeal to the mass market, yet with all the energy of the brashest of bashers. They add to this mix the stark, emotionally-distant vocals and keyboard work of the more serious and introverted art rockers.

The result is music both invigorating and enlightening. Ric Ocasek's songs have a certain adolescent charm that bounces from the speakers, yet he has carefully avoided any direct allusions to '50s rock "n" roll. The first song on the record features cheerleader-like handclapping that ends with the predictable shout, "Let's Go" (the song's title) - but the siren-like synthesizer of Greg Hawkes interrupts the chorus before it becomes oppressive. Likewise, the gimmicky, echoed voices on "Shoo Be Doo" give way to the crunching power chords of "Candy O," deflating any potential pretentiousness.

Producer Roy Thomas Baker provides the restraint that is a central ingredient in the Cars' music. The musicians are tightly controlled - particularly keyboardist Hawkes and guiatrist Elliot Easton - and their solos are never allowed to exceed the harmonic boundaries of the material. Baker also reinforces the solid structure of the songs by pushing Benjamin Orr's bass and David Robinson's drums to the forefront. The effect is much closer to a steamroller than a racy sports coupe.

At its most basic, the Cars' music is, well, basic. They have a penchant for clicking, muted background chords propelled by simple, 4/4 rhythms. They rarely vary from this formula, but the sound is saved from monotony by guitar and synthesizer lines which bring a distinctive harmonic complexity to each song.

Because their music embodies many diverse styles and is powerful yet thoughtful, the Cars are an ideal transitional rock group. They are not revolutionaries so much as popularizers. The musicians are presenting imaginative ideas in an accessible setting that allows for those ideas to be incorporated into the rock mainstream. Their music tickles both the mind and the feet, while delivering a blow square to the gut.

If the Cars are the supercharged American sedan of rock, then Gruppo Sportivo is the fiesty new European import. Their record, "Mistakes" (Sire 6066), is a witty and sprightly addition to the American market.

This Dutch group (the name was taken from an Italian poster) has a sound that is remarkably like their tiny birthplace: The compact musical structures have a striking efficiency, capable of various moods and thoughts; and the songs are clean and well-tended with clearly defined musical backgrounds.

Songwriter/guitarist Hans Vandenburg has compiled a selection of songs which are vaguely new-waveish, with strong touches of early "60s British rock. He belnds cool, wistful vocal harmonies with strumming guitars and flat rhythm sections similar to groups like Gerry and the Pacemakers, then peppers the music with strident electric keyboards. He even quotes passages from other artists' works, in contexts which are often amusting. "Superman" begins with a direct transcription of the rock 'n" roll finale to Zappa's "Lumpy Gravy" and, in a mocking tribute to the blues rockers, he parodies Clapton's hit "I Shot The Sheriff" with ironic lyrics set to the familiar reggae tune.

The lyrics by Vandenburg (his pseudonym is "Vanderfruits") are the most compelling aspect of "Mistakes," Like the early Zappa, he submits pop music and culture to a good-natured assault of incisive insights and pithy one-liners. On "Blah Blah Magazines" he ridicules record critics when he sings, "Yes it's true we steal every Tra-la we hear/Yes you're right we're like the Monkees we've got no ideas of our own."

At times, his wit is self-deprecating. Aware of his closeness to the early '60s styles, he has written "One Way Love" (a Beatle-ish ballad) with the lyrics drawn from old song titles like, "Yesterday," "Eight Days A Week," "No Reply" and "I Should Have Known Better," and with a passing reference to the Rolling Stones' "As Tears Go by."

"Mistakes" is an impressive American debut (the selections are from two previous European releases) for this promising new group. Like the Cars, they are slowly upgrading the standards of pop music. They demand just enough of their listeners to foster an environment for further work, yet they have packaged themselves in a way that is reaching many listeners. Gruppo Sportivo is proving that rock is, once again, able to laugh at itself while laughing on the way to the bank.

For several years now, the rock world has been waiting for a change. Many people assumed that this would occur with a bang instead of a whimper - with the sudden appearance of the "new" Beatles. While the next Fab Four might still be out there somewhere, groups like the Cars and Gruppo Sportive are subtly changing rock on their own. Their music is neither a bang nor a whimper. It is more like a sharp slap on the dreary jowls of rock 'n" roll.

Thanks. Rock needed that. CAPTION: Picture, Gruppo Sportivo